Catalytic wet peroxide oxidation of organic dye with in-situ generated H2O2 over bifunctional Fe-Pt@Pd/SiO2 catalyst prepared by double-metal complex salt approach

Abstract

While the Fenton reaction is efficient in wastewater treatment, the intrinsic problem of the dosage-dependent process poses another burden on ecosystem. Herein, we propose a highly efficient and environmentally-benign catalytic wet peroxide oxidation (CWPO) of methyl orange (MO) using in-situ generated H2O2 from hydrogen and air instead of ready-made H2O2. Pt@Pd/SiO2 and Pd@Pt/SiO2 catalysts were prepared by double-metal complex salt approach, and they were combined with soluble Fe salt (CWPO-I) or impregnated Fe (CWPO-II). The MO degradation rate of Pt@Pd/SiO2 for CWPO-I was 2.5 times faster than that of the conventional PdPt/SiO2. This can be rationalized in terms of Pd-enriched surface with strong interaction between Pt and Pd. Moreover, bifunctional Fe-Pt@Pd/SiO2 catalyst demonstrated outstanding activity in promoting CWPO-II with in-situ generated H2O2, even outperforming its counterpart with ready-made H2O2. This new approach offers an efficient water remediation method free from addition and generation of any undesirable chemicals affecting environment.